Dino-Birds: 2 (Avimimus)

Dino-Birds: 2 (Avimimus) ~ Fossils found during the last 20 years show what some dinosaurs may have been covered with feathers or fur. Sinosauropteryx was a small, 1 m long meat-eater that lived 135 million years ago in China. Fossils of Sinosauropteryx show that parts of its body were covered not with the usual reptile scales, but with feathers. 

The overall snape of Sinosauropteryx shows that, despite being feathered, it could not fly. The feathers of Sinosauropteryx may have been for cammouflage, for visual display, or to keep it warm. Suggesting it was warm blooded.

Avimimus may have evolved feathers for warmth of for camouflage

Avimimus was a small, light dinosaur, its fossils come from China and Mongolia, and date from 85-82 million years ago. 

The 1.5 m long Avimimus had amouth shaped like a bird's beak for pecking at food. The fossil arm bones of Avimimus have small ridges of the same size and snape as the ridges on bird's wing bones, where feathers attach.

In modern science, any animal with feathers is a bird, so some experts say that feathered dinosaurs or even reptiles, but birds.

Some experts say that birds are not really a separate group of animals, but a subgroup of dinosaurs that lives on today, and they should be regarded as feathered dinosaurs.

See also about Growth and Age Dinosaurs

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Growth and Age Dinosaurs

Growth and Age Dinosaurs ~ No one knows for sure how fast dinosaurs grew, how long they took to reach full size, or how long they lived. Most estimates of dinosaur growth rates and ages come from comparisons with today's reptiles. 

Tyrannosaurus may have taken 20-50 years to reach adult size

Some reptiles today continue to grow throughout their lives, although their growth rate slows with age. Dinosaurs may have grown fast as youngsters and slower as adults, never quite stopping until they died.

Estimates for the age of a full-grown meat-eater such as Tyrannosaurus range from 20 to more than 50 years. Full-grown, small meat-eaters such as Compsognathus may have lived to be only 3-10 years old.

A giant sauropod probably lived to be 50 years old, or even over 100 years old. Like many reptiles today, a dinosaurs growth rate probably depended largely on its food supply.

Dinosaurs probably ate a lot and grew fast when food was plentiful, and slowed down when food was scerce. During its lifetime, a big sauropod such as Brachiosaurus would have increased its weight 2000 times (compared to 20 times in human).

See also about Dinosaur Fossil-Hunters

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Dinosaur Fossil-Hunters

Dinosaur Fossil-Hunters ~ Many dinosaur were found in the USA in the 1870s-90s by Othniel Charles Marsh and Edward drinker Cope. Marsh and Cope were great rivals, each one trying to find bigger, better and more dinosaur fossils than the other. The rivalry between Marsh and Cope extended to bribing people to smash each other's fossils with hammers, planting fake fossils, anda damaging food, water and other supplies at each other's camps in the Mid-West.

STAR FACT :
One of the first great fossil-hunters in the USA was Joseph Leidy, who found troodon in 1856.

Cope and Marsh found and described about 130 new kinds of dinosaurs between 1877 and 1897. Joseph Tryrrel discovered fossils of Albertosaurus in 1884, in what became a very famous dinosarur region, the Red Deer River area of Alberta, Canada.

Lawrence Lambe found and described many North American dinosaur fossils, such as Centrosaurus in 1994.

German fossil experts Warner Janensch anda Edwin Hennig led expeditions to east Africa in 1908-12, and discovered Brachiosaurus anda Kentrosaurus.

From 1933 Yang Zhong-Jiang (also called CC Young) led many fossil-hunting trips in verious parts of China.

Jose Bonaparte from Argentina has found many fossils in that fegion, including Carnotaurus in 1985.

See also about Legs and Posture Dinosaurs

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Raptors

Raptors ~ Raptors' is a nickname for the Dromaeosaur group. Reptor is variously said to mean 'plunderer', 'thief' or 'hunter' (birds of prey are also called raptors). Dramaeosaurs ware medium-sized, pwrful, agile meat-eating dinosaurs that lived mainly about 110-65 mllion years ago.

Raptors - Dromaeosaur

Most dramaeosaurs were 1.5-3 m from nose to tail, weighed 20-60 kg, and stood 1-2 m tall. Velociraptor lived 75-70 million years ago, in what is now the barren scrub anda desert of Mongolia in Central Asia.

STAR FACT :

On each foot, a dromaeosaur had alarge, curved claw that in could swing in an arc to slash through its victim's flesh.

Like other raptors, velociraptor probably ran fast and could leap great distances on its powerful back legs. The dromaeosaurs are named after the 1.8 m long Dromaeosaurus from North America. One of the least known of the group, from very few fossil finds.

The best-known raptor is probably Deinonychus. The Large mouths of dromaeosaurs opened wide and were equipped with many small, sharp, curved teeth.

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Legs and Posture Dinosaurs

Facts About Dinosaurs ~ All dinosaurs had 4 limbs. Unlike certain other reptiles, such as snakes and slow-worms, they did not lose their limbs through evolution. Some dinosaurs, such as massive, plant-eating sauropods like Jamenschia, stood and walked on all four legs nearly all the time. The all-fours method of standing and walking is called "quadrupedal". Some dinosaurs, such as nimble, meat-eating dromaeosaurs like Deinonychus, stood and walked on their back limbs only. The front two limbs were used as arms.

Legs and Posture Dinosaurs

The Back-limbs-only method of standing and walking is called "bipedal". Some dinosaurs, such as hadrosaurs like Edmontosaurus, could move on all four limbs of just on their back legs if they chose to. The two-of-four-legs method of standing and walking is called "bipedal/quadrupedal".

Legs and Posture Dinosaurs

Reptiles such as lizards and crocodiles have a sprawling posture, in which the upper legs join the body at the sides. Dinosaurs had an upright posture, with the legs directly below the body. The more efficient upright posture and gait may be one major reason why dinosaurs were so successful compared to other animals of the time.

Legs and Posture Dinosaurs such as lizards and crocodiles

Don't forget, see also about Age of Dinosaurs.

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Age of Dinosaurs

Fact About Dinosaurs ~ The Age of Dinosaurs corresponds to the time period that geologist call the Mesozoic Era, from about 248-65 miliion years ago. The Mesozoic Era is devided into three shorter time spans - the Triassic, Jurassic and Cretaceous Periods.

Age of Dinosaurs

In the Triassic Period, 248-208 million years ago, the dinosaurs began to evolve. During the Jurassic Period - about 208-144 million years ago - the dinosaurs reached their greatest size. The Cretaceous Period is when dinosaurs were at their most varied - about 144 - 065 million years ago. In the Triassic Period, all the continents were joined in one supercontinent - Pangaea. In the Cretaceous Period, Laurasia and Gondwana split, and the continents as we know them began to form. In the Mesozoic Era, the major land-masses gradually moved across the globe in a process known as 'continental drift'. The joining and separating of the continents affected which kinds of dinosaurs lived where.

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